Our 7-y.o. daughter was just diagnosed with KD after a 9 day 103+ fever (and being sent back from the ER to home the first time after 5 days being told it could take up to 10 days). We were almost sent home the second time when the head of pediatrics happened to walk by, see her, and scolded the younger ER Dr and diagnosed her rather quickly.

She was given what we assume is the standard IVIG + asprin treatment. The first night was quite concerning as once the IVIG reached peak dosage she had some serious side-effects to it, it needed to be flushed, and then restarted again with a much lower dosage for a longer period of time. After that first night everything went well and on the third day of treatment she was finally sitting up, cheerful, and laughing again.

The IVIG treatments finished and we had to wait another 12 hours for the ECG and then sent home. We arrived home at ~4 pm today and the little one started complaining about a headache in her forehead. She's never had a headache before - to our knowledge - and so we gave her a little Tylenol to help and she fell asleep rather quickly. 6 hours later she woke up crying and saying that it is much worse and that the lights hurt (migraine symptom?).

I've been searching online since then trying to discern if she's just having a typical reaction to IVIG/asprin treatments, or if this could be a serious side-effect or continuation of the KD. None of the literature I've come across seems to link KD to headaches, except for this study, which found a smallish percent of people who received IVIG ended up suffering from aseptic meningitis:

Reading this forum leads me to believe that this "headache" phenomenon isn't isolated to us, but I figured I'd post and make see what the other experiences here were. If you went back to the ER, what was done (if anything)? Did the headaches just go away? Were there any post-treatment side-effects we should be watching out for? Did the headaches go away with sleep and fluids? She's asleep right now, but if she wakes up with the headache and crying, I can't see myself doing anything other than taking her back to the ER.